When cooking certain types of food in an oven, it is often desirable to ensure that all sides of the food item are equally exposed to the heat source within the oven. To this end, a rotating platform may be used within the oven, with the platform having smaller pallets thereon that rotate relative to the platform. Such an oven is described in U.S. Pat. No. 1,163,807 to Bower et al.
Such ovens are subject to drawbacks. For example, when inserting food items into such an oven, the food item may be pushed too far into the oven, causing the food item to fall off the pallet as it rotates, possibly ruining the food item.
In addition, it is often desired to simultaneously cook different types of food items having different cooking times, the operator of such an oven will have to remember which food items have been placed on which food pallets, as well as their associated cooking times. This can be confusing, and may lead to undercooking or overcooking of food items. While in a factory setting, large quantities of items of the same recipe are cooked simultaneously, in a restaurant situation it is usually necessary to have the ability to cook a variety of different recipes, each requiring a different cooking time, and often requiring different cooking conditions.
For pizzas, there are a variety of known ovens. It is well-known that the general public considers a pizza cooked in a wood fired oven directly on a stone deck or surface as a superior product. Not only is the product better, the ambiance such an oven produces is associated with an upscale image and is therefore commercially important in its own right. However, because of the inherent labor costs and production limitations of this type of oven, no fast food operator has yet been able to offer such a product.
Standard wood-burning ovens have major differences in temperature thru-out the oven, partly as a result of the fire being built off to one side, and partly as a result of the front opening, and partly because a wood fire does not burn at a set uniform temperature. As a result, it takes a highly skilled operator to keep turning the pizzas as they are baking, as well as shifting them to different parts of the oven depending on size, amount of toppings, the degree of topping moisture and thickness of crust. Indeed, patents have been issued for pizza peels that allow the operator to partially rotate the pizza without removal from the oven to help in the constant turning. In the event several pizzas are being baked at one time, the job becomes much more complicated and the results are often an improperly cooked product as well as high labor cost. With the advent of high-speed rotary decks, ovens such as described, for example, in U.S. Pat. Nos. 6,146,677 and 6,250,210, a pizza can be cooked in 90 seconds but does require turning the pizza during that time interval. Without an automatic means of control, multiple cooking of pizzas or other food items with varying recipes in a “restaurant mode” is virtually impossible.
A wood burning pizza oven has a stone floor, and the pizza is placed directly on the floor, resulting in direct cooking of the crust or shell of the pizza, which is one feature that gives superior cooking. It is to be appreciated that, in a raw pizza, a large proportion of the weight is water, and indeed, for the ingredients or toppings, water can comprise 90 percent of the weight and may comprise 50 percent of the weight of the shell. As is known, browning of the shell, or even desired portions of the toppings, cannot occur until relevant portions have been cooked for long enough to drive off all the moisture, so that the temperature can then be raised above the boiling point of water, namely 100° C.
In such a wood burning oven, the bottom of the shell is immediately brought into contact with the hot floor of the oven, which results in rapid and even heating and cooking of the shell. The porosity of the floor also helps to dissipate water vapor given off from the shell, resulting in desirable, uniform browning and cooking of the bottom of the shell.
However, such a traditional oven requires considerable skill to operate and each individual pizza requires a large amount of attention, resulting in high staffing requirements. Typically, the temperature within such an oven is not uniform. Each pizza is placed in the oven, and then has to be continually monitored and moved within the oven, so that it is cooked uniformly. Sometimes, the top will not cook or brown at the same rate as the shell. A skilled pizza chef will often raise a pizza that is almost cooked on a pizza peel and hold it close to the roof of the oven, so that radiant heat from the roof will finish the browning process for the top of the pizza. Clearly, all of this requires a skilled pizza chef and is time consuming.
An alternative approach to cooking pizzas, commonly used in larger restaurants and where high volume is a premium, e.g. in restaurants specializing in take out or delivery of pizzas, requires different types of ovens and techniques. It is common to place each pizza on a tray or screen that is perforated. Here, it should be borne in mind that a raw pizza is a difficult object to manipulate, as the raw dough is flexible and has no rigidity. Thus, by forming pizzas on such a tray, handling of the pizzas is greatly facilitated and can be done by unskilled personnel. An additional advantage is that one can provide trays of different sizes corresponding to different pizza sizes, thereby giving automatic portion or pizza size control.
After each pizza has been assembled on a tray of appropriate size, the pizza and the tray are placed in an oven, until the pizza is cooked. This is often done, even where the oven itself has a proper, flat deck and is intended for traditional cooking of pizzas. In large establishments, pizzas are often delivered to and from the oven on conveyors that pass through the oven, and in this case, it is almost always necessary to retain the pizza on a tray. Such conveyor systems subject each pizza to the same cooking time and conditions, and provide no flexibility in terms of enabling selection of different cooking times, conditions, etc.
Additional advantages of using such trays are handling and storage of the pizzas both before and after cooking of them. The pizzas on the trays can be stacked on shelves.
However, cooking a pizza on a tray or screen, even if perforated, can never simulate the cooking characteristics of a traditional pizza oven where the pizza is cooked directly on the hot deck of the oven. Heating of the bottom of the pizza is indirect, and the tray or screen necessarily interferes with dissipation of moisture from the bottom of the pizza. Hence, browning of the bottom of the shell is quite different.